Schedule Compression and Time-Cost Trade-Off - Construction Project Scheduling and Control - page 215

III. Contractual approach
IV. Scheduling
V. Materials management
VI. Construction work management
VII. Field labor management
VIII. Start-up phase
A review of these techniques underscores the importance of early planning.
For some projects, the decision to compress the schedule may be made during the
construction phase. Other projects, such as the Northridge case study, are carefully
planned from the moment the project is conceived through completion.
The author suggests 10 techniques (not in any particular order):
1. Revisit or study the schedule thoroughly to find any errors or unnecessary logic or
constraints : The most common pitfall is using the finish-to-start (FS) relation-
ship when a start-to-start (SS) relationship with a reasonable lag can work. For
example, suppose that the logic is that activity B in Figure 8.1a cannot start
until activity A is finished (i.e., day 10). After checking the situation, we find
that activity B can start only after a certain portion of activity A is finished
(e.g., 40%). In this case (Figure 8.1b), activity B can start as early as day 4,
which saves 6 days. If you prefer to use only FS relationships, then split the
predecessor into two or more activities (a detailed discussion can be found in
Chapter 5).
2. Fast-track the project (as mentioned in Chapter 5) : Fast-tracking means start-
ing construction before the design is completely finished. Conceptual design
must first be done; the detailed design follows in stages. The construction of
each phase (or component) follows the detailed design of the phase while the
next phase is being designed (see Figure 8.2). The decision for this option
has to be made very early during the project's conception and requires a spe-
cial agreement/contract between the owner, the designer, and the contractor.
There is a good possibility that with this option, the contract is design/build,
which means that the owner signs a contract with only one entity for both
design and construction services. Fast-tracking has its disadvantages as well,
especially when it is not well planned.
Figure 8.1 Time savings difference between (a) finish-to-start (FS) and (b) start-to-start (SS)
relationships